Problem Solving

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Wed Oct 14, 2020 12:26 pm

E-GMAT

What percentage of odd numbers lying between 1 and 30 divide 7,700 completely?

A. 20%
B. 25%
C. 30%
D. 33%
E. 40%

OA D

Solution:

(Note: We will assume that “between 1 and 30” means “between 1 and 30, inclusive.” Also, the question should have said “approximately what percent …”)

The odd numbers between 1 and 30 (inclusive) that divide 7,700 completely are 1, 5, 7, 11 and 25.

Since there are (29 - 1)/2 + 1 = 28/2 + 1 = 15 odd integers between 1 and 30 (inclusive) , the percentage of odd numbers that divide 7,700 completely is:

5/15 x 100 = 1/3 x 100 = 33 percent

Answer: D